Misfire caused by Alternator?

[And_44]

Hey there,

So after replacing many parts with other to diagnose a misfire in all rpm ranges I have a question.

The ignition coil/module receive there voltage directly from alternator.

My problem.... I get spark to all four ports on my coil, BUT with the wires attached I'm not getting enough charge through the wire that is furthest away on the coil from the +/- posts on the back to trigger my timing light, I can switch my wires on the posts and the no signal follows the one post on the coil and not the wires. I've swapped my ignition module with 2, and my coil with 3. All same results. The

So my question could the alternator when warm/hot be putting out a lower voltage to not put enough of a spark on the posts furthest away from the +/- on the back of coil?

 

[Indian]

The alternator would not cause a misfire issue.

 

[DSM1G90]

tried new wires? those carbon fibre wires do get internal breakage inside after they get some age on them.

 

[97 Talon Esi]

have you tested the resistance at the plug that connects to the coil.Another thing to look at is the power transistor it can cause intermittent misfires.

 

[And_44]

Was the alternator. Replaced it with a new one and works wonders. Wires, plugs are brand new. I've swapped 3 known good coils and 2 modules and had same issue. I swapped the CAS, throttle body with new seals and good TPS/ISC, and ECU and same issue.

When I swapped the CAS and had to adjust the timing I realized the coil wasn't getting enough power to send a signal down the 1 wire, but was getting a signal in the 4 wire, when I removed the offset wire I was getting a spark but was pretty weak. How the coil is set up with the power supply directly behind the one post and the other being offset when what power was getting to coil to ignite the plugs it was taking the shortest route possible and what was left was going to the offset wire. I flipped the wires and the problem followed the posts on the coil so ruled out my wires. But this was the 3rd coil I had in there and couldn't of been the coil(s). The ignition module was the 2nd one installed and couldn't of been that.

I tried looking for something in ignition to regulate the power but could only find that the Alternator had an internal regulator. When I thought back to when problem started (ie I replaced exhaust manifold, new PCV, started using cheap ARCO/AMPM gas) it was easy because those where the most noticable differences in what I did with car and only changes made. But I remembered that when I replaced the manifold my water inlet pipe o-ring leaked a good amount of coolant and when that leaks it leaks onto your Alternator.

This hit me like a ton of bricks. The Alternator is a mass of coils that when cool are fine, but when heated they expands and can cause lose of contacts/charge, and it quickly cools when car is not running, then quickly reheats.

 

[DSM1G90]

Glad you got your problem searched out. that ALT was getting ready to die then and you got it out in time.

good luck then - DSM

 

[Juan Hernandez]

Was the alternator. Replaced it with a new one and works wonders. Wires, plugs are brand new. I've swapped 3 known good coils and 2 modules and had same issue. I swapped the CAS, throttle body with new seals and good TPS/ISC, and ECU and same issue.

When I swapped the CAS and had to adjust the timing I realized the coil wasn't getting enough power to send a signal down the 1 wire, but was getting a signal in the 4 wire, when I removed the offset wire I was getting a spark but was pretty weak. How the coil is set up with the power supply directly behind the one post and the other being offset when what power was getting to coil to ignite the plugs it was taking the shortest route possible and what was left was going to the offset wire. I flipped the wires and the problem followed the posts on the coil so ruled out my wires. But this was the 3rd coil I had in there and couldn't of been the coil(s). The ignition module was the 2nd one installed and couldn't of been that.

I tried looking for something in ignition to regulate the power but could only find that the Alternator had an internal regulator. When I thought back to when problem started (ie I replaced exhaust manifold, new PCV, started using cheap ARCO/AMPM gas) it was easy because those where the most noticable differences in what I did with car and only changes made. But I remembered that when I replaced the manifold my water inlet pipe o-ring leaked a good amount of coolant and when that leaks it leaks onto your Alternator.

This hit me like a ton of bricks. The Alternator is a mass of coils that when cool are fine, but when heated they expands and can cause lose of contacts/charge, and it quickly cools when car is not running, then quickly reheats.

I'm having the same issue with mine I thought it wasn't the alternator but looks like it is

 

[ARCHangel8788]

I'm having the same issue with mine I thought it wasn't the alternator but looks like it is

Have you had it tested? Buddy just did a 4g swap in his mirage and was having this problem but found out it was the wires leading from the alt. So he bought a new one for no reason

 

[Juan Hernandez]

yea I'm going to test it today this happen to me last night but I'm pretty sure it's the alternator.... the battery is drained and when I cable jump it , it doesn't last to long while it's on and when I accelerate that's when the misfire begins and stutters
ORIGINAL ALTERNATOR -1990

 

[ARCHangel8788]

Nice. Keep us updated. Hopefully an easy fix.

 

[1990TSIAWDTALON]

Go with a 96 Galant alternator. Has more amps, is plug and play and bolts up directly.

 

[Juan Hernandez]

Go with a 96 Galant alternator. Has more amps, is plug and play and bolts up directly.

Thanks brother I'll look into that

 

[1990TSIAWDTALON]

I have an O'rielly's unit, lifetime warranty. Works great. That's what this forum is all about, sharing idea's, some good, some not so good, but a lot of good people on here.

 

[Juan Hernandez]

Alright guys so I have another problem hopefully I could get a better answer. recently I replace my clutch+flywheel+clutch fork+throw out bearing+slave cylinder.. etc
So the problem is that I'm hearing a rattling in the transmission when I accelerate it (car is in no motion) kinda sounds like I'm running diesel but goes away when it goes back to idle or when I engage the clutch.

Some people told me it's normal???

 

[ARCHangel8788]

Umm. I don't think that's normal. Mine doesn't do that nor anyones i know. Wish i an answer for you but i would check clutch adjustment and so forth.

 

[Dsmkauai]

Post a vid of the noise. Shouldn't be any noise like what you are saying. What kind of parts did you use? Did you properly torque and lock tight the bolts? Did you properly bleed and adjust the clutch?

 

[Juan Hernandez]

Hello everyone so the problem was irrelevant... seems like it was just some clutch chatter and I just I had break the clutch in.

I should of known better but better safe then sorry

thanks for all your help guys !